Screw machine



NOV 6 1945. w. E. JOYCE ET AL 2,388,612

SCREW MACHINE Filed Jan. 12. 1942 `3 Sheets-Sheet 1 ATTORNEYS Nov. 6, 1945.

w. E. JOYCE ET AL 2,388,612

SCREW MACHINE Filed Jan.'12, 1942 5 sheets-sheet 2 INVENTOR wxLuAM E. JOYCE BY @am v-wea M v MW ATTORNEY 5 Sheets-Sheet 3y W. E. JOYCE ET AL SCREW MACHINE Filed Jan. l2, 1942 I WILLIAM Nov. 6, 1945.

Patented Nov. 6, 1945 UNT-TED STATES PATENT cFFIcE I. Wilson, Dayton, Ohio, assignors to The City Engineering Company, Dayton, Ohio, a corporation of OhioV Application January 12, 1942, serial No. 426,484 2 claims. (ci. :s2-2s) This invention relates to a screw machine.

It is an object of the invention to provide a screw machine having an independent variable speed drive for the screw machine cam shaft so ask to provide 'an infinite variety of speeds in order to secure the maximum number ofv pieces per hour-.according to theY type kof piece and the metal from which it is being made.

It is a further object of the invention toA provide means of adjusting the speed of the cam shaft while the machine is operating so that the effect of the adjustment on the making of the parts can be observed simultaneously with the adjustment. By this means the adjustment can be effected so that the tool will do the best work which can be determined primarily by observing the machine as it operates; Heretofore in the art it has been necessary to stop the machine and make a. complicated series of adjustments in variation of speed by the use of pickoi gears and other similar mechanisms. It was, therefore, impossible to make the adjustment continuously both to increase or decrease speeds while observing the action of the tool on the Work. Furthermore, such adjustments to the prior art only permitted xed variations in speed whereas the subject of the present invention is to provide an infinite variety of speeds in combination with various orienting speeds, depending upon the setting ofl the adjusting mechanism.

T It is a further object of the invention to provide a straight line spindle drive likewise adjust# able to an infinite variety of speeds so that the correct combination of speeds for the performance of the particular Work desired can be secured by adjusting the speed of the cam shaft and of the spindle to provide a. precision adjustment for high production and fine workmanship; and to provide such an adjustment, when once made, which will bring vabout a combination of speeds of the spindle and cam shaft that the two shafts will be respectively operating in synchronism at their maximum combination eniciency. Y

It is a further object to provide, in this combnation of drives for the spindle and cam shaft, an arrangement by which if the drive shaft drive ceases to operate, then the cam shaft drive will be rendered inoperative stopping the cam shaft and preventing the wrecking of the tools. Heretofore, in the art, there has been no way by which this disadvantage could b'e overcome except for the operator to shut down the machine which cannot be done quickly enough manually to prevent the wrecking of the tools.

It is a further object of the invention to provide an interconnected electrical supply system whereby when one of the drive motors, such asrthe main drive motor for the spindle, is overloaded then all of the remaining motors including the drive motor will be disconnected from the power source and by this means -a wrecking of the tools is prevented.

It is a further object'of the invention to provide a mounting for the motor and change speed mechanism in such a manner on the base casting as to rigidly position, support and align it and to maintain a low center of gravity and to provide in combination therewitha straight line drive shaft mounted in self-aligning bearings on the base casting adjacent the bottom thereof close to the floor to give the maximum rigidity to the alignment of the shaft and the maximum reductionof vibration of gyroscopic movement of the shaft. This also provides a straight line drive with direct power take offs to the spindle and attachment'mechanisms at spaced points between the bearings.

It is a further object of this invention to have such an adjustmentA to the mechanism that you can get fractional number of parts for time interval up to the maximum machine capacity 'as distinguished from getting even number of parts with the adjusting mechanism of the prior art.

YIt is a further object of the invention to provide adjusting mechanism for the cam shaft which has a predetermined number of speed adjustments as guides forv the operator withV an infinite number of adjustments between each guide adjustment and in combination with this infinite variation of adjustment a multiple belt and pulley arrangement' providing a large number of speed changes and ratios.

Inthe drawings:` Y

Figure 1 is an end elevational view of a screw machine having portions thereof in cross-section to show features of this invention.

Figure 2 is a side elevational View of a screw machine having portions thereof broken away to show features of this invention.YV

Figure 3 is an elevational view indicates cam shaft speed.

Figure 4 is an elevaticnalview of a dial indicating spindle speed. e

Figure 5' is a cross-sectional'view of the drive shaft for the screwmachine.

Figure 6 is a schematic Wiring diagram of the electrical controls for the screw machine.

In this invention there is provided an independent mo'tor drive with a variable speed drive of a dial which The cam shaft drive is through a variable speed mechanism through an independent motor.

mechanism has I3 major stQpS Qr positioning points to guide the operator in selecting the speeds, but between each point the variation of speed can be innite. The drive pulley on the change speed shaft can either drive direct from a small pulley to a large one driving the cam.

shaft or vice versa or through a pick off pulley' 0.1.1Y the ,side of the base casting giving three separate combinations with each of the I3 .steps with an ininite variation of speed between the stops..

The independent adjustment ofthe two motors for cam shaft and spindle shaft permits of bringe ing a combined relative speed adjustment in the final adjustment which permits of adjusting the tools to their maximum efficiency depending upon the type of the piece, the nature of the tool and the metal and of. doing this while the machine is running.

The screw machine consists oi a base casting Ill having a hollow interior II for enclosing the drive Shaft I2. The base casting I has an extendedhQltion I3 Within which a variable speed drive unit I4. is positioned.

The variable speed drive unitA I 4 is directly connected to an electric motor I5 which has a iiange l5! The flange I6 is bolted to. the extended portion I3. of the base casting IIl by means of suit-V able bolts, I1,-

The variable speed drive unit I4 is of any suitable type having infinite changes in' its speed range. The variable. speed drive unit may be of the hydraulic type Or can be a mechanically coupled type of unit. vIn any instance, however, the variable speed driveunit'can have its output shaft varied in speed over a Wide range and in an ininite number of steps or gradual changes. A suitable speed adjustment control handle I8 extends from the. variable speed drive unit I4 for changing the speed or the output shaft I9.

The output shaft I9 of the variable speed drive I4; is connected to the drive shaft I2 by means ofg. flexible coupling 20. The drive shaft I2 is supported by means of self-aligning bearings 2I and 22, to` be. hereinafter. described, which are positioned within support webs 23 and 24 respectively extending upwardly` from the bottom 'wall 25 of the base casting I0. L

The drive shaft I2 carries a drive pulley 25- which is keyed upon the. shaft I2 by meansy off the key 21 and is secured in position by means of the set screw 28. l

The base casting I6.. supports a frame 29- which car-ries a headstock 3.0A having a spindle 3|w suitably bearinged therein. The spindle13t carries a pulley 32 which is engaged bya belt 33 extending thereover. The belt 33 also. engages theV drive pulley 26', thereby providingmeans for driving the spindle 3| from the. drive. shaft I2.

A tool head is supported upon the frame 29 and is adapted to. carry a plurality. of turning] @001s- Tlle terrine tools carried bit the toer head 3.4. are adapted to' engage. a work piece carriedi by the spindle 3l for turning work of various types.

The turning tools are actuated by means of cams 35 carried upon a cam shaft 36 which is bearinged to the frame 29 by means of the bearings 31 and 38. 'Ihe surface of the cams 35 is generated. to produce the deslredllletien by the Work tool to make a cut'upon thelwprk piece of a desired contour.

The cam shaft 36 is driven by means of a worm and worm wheel drive contained within the housing 33. The worm is carried upon a shaft 40 which extends from the housing 39. A pulley 4I is carried upon the shaft 40 and has a belt 42 extendine therecver into engagement with a pulley 43 carried upon the output shaft 44 of a variable speed drive unit 45 driven by an electric motor 46.

The variable speed drive unit 45 and the electric motor 46 are suitably carried upon the base casting I0 by means of a support frame 4'I. The Variable ASpeed drive unit 45 may be of any cenventional type. wherein the output shaftthereof can have the speed changed in an innite numbel Qi .Steps or in a gradual change.. This variable speed drive unit 4.5. can beof the same type as the variable speed drive unit I4 for the drive straft |11. A speed adjustment. control handle 48 is provided for the variable speed drive unit 45 for changing the Speed of rotation of the output Shaft 4.1L`

The pulleys 4I and 43 are of the double pulleyy type Se that the range of the variable speed de-A livery unit 45 can be raised. or lowered depending uren the pulley set; connected by the belt 42.

'Elle cams 35 earriediunon the cam shaft as are adapted to move the. worktools. with respect te the wer-1s pieceupcn `the spindle al through a. series of leversj and 5g.. .The leverv 49 is pros. vided. with a cam follower furor. engagingthe llr'fe of; thecam 35.. wThe. contour ofthe cam 3.5. tllll eorltlFQls the movement of thetool with ITESDQQ 12o the. Wolk' piece and the. speed' of mta-n tion of; the. calm determines. the period of time that thetool will be in olf-.out of engagement with the Work; piece..A I

the. Cam shaft 3.6i isdriven by means of a variable Spid; dlt-ive unitthe vspeedof rotation of the, Cam' Shaft, will be. innitely variableo-ver the range oi operation ortho variable speed drive unit 45. The drive.arrangement/ottima invention forthe` cam shaft. 361also provides means hfleby the Speed] of rotation or the cam shaft (itA can be changed Whilexthe screw machine. is operating. There arerno gears or; other mechanical equipment. to.l change when .the speed of the (1am Shaft. is to b ealtered,.but rather the variable speed drive4 unit 45, permits an infinite number of speeds. of theoutputshaft'4z4: thereof throughout its; range of operation-.1 Therefore, the speed Vof Operation of thexcamshaft vcan .be controlledl or changedl when the. screw machine is operating.

A n indicatingdialnl isprovided on the variable Speed drive. uniti td indicatethelrange within which the unit is operating. This dial' 52 is. shown in. Iigu're4 3., 4'The-faceof' the dial 52 is provided with indicia thereon. and' vin the instance of thisinvention theIdialf-faceisdividedf into 13 segments. Eachsegmentrepresents a ran-ge of speeds. or oper-ation. or the vcam shaft. The-'particular range. ot the. cam` shaft driven-nit of' this invention is from: lt R. P; M. to 20l R. P. M: Sincethe: speed or rotation of the. cam, shaft 336 determines. the. number or pieceswhich are pro.-A Clued; 11129.11. the. screw. machdielitf. can readily be seen that the number 'or pieces produced bythe "machine can be varied over a considerable range,

The 'slower the rotation of the'cam shaft 36 the fewer the number ofl pieces produced.

As Aheretofore disclosed the spindle 3| is driven by means of the variable speed drive Vunit I4, the drive unit |4 being innitelyvariable throughout its entire speed range. Therefore, the spindle 3| of the screw machine is capable of being driven at any speed, dependent only upon the setting of the variable speed drive unit I4. The drive unit of this invention is capable of speed variation from about 680 R. P. lvl. to 6000 R. P. M. A dial 53 is provided for the variable speed drive unit I4 and has'indicia thereon to indicate the range within which the spindle 3| is operating. The indicia merely provides means lwhereby the operator ofthe machine. can orient the speedl of rotationcf the spindle within a general speed range. After obtaining the general range the operator can then adjust the variable speed drive unit I4 by means of the handle I8 until the exact rotation desired is obtained. Y

It is to be understood that the screw machine is preferably operating during the final setting of `the speeds of operation of the cam shaft 36 and the spindle 3| so that the operator can inspect the results of operation upon the workpiece to determine the most efficient operatingl point for the particular material being used.

It is well known that in manufacturing processes the quality of raw stock will vary to some extent and if a machine is set to workupon raw stock of a particular quality that it may not be set Afor the most efficient operation upon raw stock ofa slightly different quality. Therefore, this invention provides an apparatus wherein the speeds of operation of the spindle and the cam shaft can be Varied individually to alter working conditions slightly to. meet the Variance in quality of raw stock.

The drive shaft I2 of the screw machine is supported upon the self-aligning bearings 2| and 22. The bearing 2| consists of a self-aligning ball bearing set 54 which is carried upon a bushing 55 pinned to the shaft I2 by means of the pin 56. The inner race 5'I of the ball bearing set 54 is retained upon the bushing 55 by means of the nut 58 while the outer race 59 is retained in position by means of a sleeve 6I0 secured between the cover 6I and the race 59. This assembly is supported f within the web 23 which extends upwardly from the bottom wall 25 of the base casting I0, thereby providing a rigid bearing support for the drive Shaft I2: Suitable oil seals 62, 63 are provided in the cover 6I and the web 23 to retain lubricant upon the self-aligning ball bearing set 54.

The web 24 extending upwardly from the bottom wall 25 of the base casting Ill carries the second bearing 22 for the drive shaft |2. This bearing is supported by means of a plate 64 which is bolted to the web 24 by means of the bolts 65. A sleeve 66 is positioned Within the plate 64 and carries a self-aligning ball bearing set 61 Within a recess 68. The inner race 69 of the ball bearing set 6l is supported upon a bushing 'I0 and is secured in position by means of a nut II threaded upon the end of the bushing 1|). The outer race 'I2 is carried by the sleeve 66 and is retained in position by the ring 13. An oil cup 14 is carried by the sleeve 66 for directing lubricant to the self-aligning ball bearing set 61.

As will be seen from Figures 2 and 5, the drive shaft I2 is directly in line with the output shaft I9 of the variable speed drive unit I4. Also, the webs 23A and 24, which carry the self-aligning vbearings 2| and 22; are positioned with thebearings 'closely adjacent thebottom wall 25 of the -base .casting I9. The arrangement thus provides a rigid support for the drive shaft I2 to prevent 'vibration thereof. A pulley 'I5 is secured to the end of the drive shaft 'I2 and .hasa belt 'I6 extending thereover Ainto engagement with a pulley I1 positioned upon a combination centering, drilling and tappingattachment 18. The pulley 15. and the belt 'I6 thus provide' means for driving the tools carried by the combination attachment 18. Also, the speed of operation of the tools carried by the attachment .13 `are variable over the same range of operation as .the spindle 3| since the spindle is driven from the same drive shaft I2. f

A pulley set 'I9 is secured to the drive shaft I2 and is adapted to have a belt associated therewith for driving a slotting mechanism adapted tobe attached upon the screw machine. The slotting apparatus is an attachment and is not shown in the present drawings. However, the slotting attachment Ais driven at a proper speed since the drive pulleys T9 for the same are carried upon the -drive Vshaft I2 which is controlled by the variable speed drive unit I4.

As-heretofore described the spindle 3| is driven by meansof a belt 33 extending between the pulleys 32 and 26. `If the belt 33 should break the spindle 3| would stop rotating, but the cam shaft 36 would continue to rotate to advance the tools upon the tool head 34 into engagement with the now stationary. work piece, whereby the tools Vwould` be damaged. Therefore, itbecornes essential that the cam shaft 36 shall be stopped when the belt 33 should break, or for some other reason should stop driving the spindle 3|.

An idler pulley 8U is carried upon a yoke 8| -pivoted uponba pin A82 carried upon a bracket 83 secured tothe base casting I0. The idler pulley 80 is retained in engagement with the belt 33 by means of a spring 84 which is positioned betWeen'the yoke 8| and a Stud 85, secured to the base casting I0. The idler pulley 8|)l thus tensions the belt 33 to maintain the same in the proper taut condition for driving the spindle 3|.

The yoke 8| carries a pin 86 which is adapted to engage a plunger 8'I of an electric switch 88 secured to the wall of the base casting I0. The pin 86 extends through a slot 89 provided in the 'base casting wall. A stop 90 is provided on the base casting wall I to engage the yoke 8| to prevent the pin 86 from breaking.

The switch 88 is located in the holding circuit of a starting controller 9|. The starting controller 9| (see Figure 6) is provided with a series of blades 92, 93 and 94 for making circuit to the spindle drive motor I5 and the cam shaft drive motor 46. A blade 95 establishes a holding circuit for the solenoid 96 of the controller 9| through the overload relay 97 and the electric switch 88. Aslong as the switch 88 and the overload 9'I are closed the spindle drive motor I5 and the cam shaft drive motor 46 will be supplied with current.

If the belt 33 should break or for some reason leave the idler pulley the yoke 8| will pivot about the pin 82 lcausing the pin 86 to strike the plunger 81 and open the switch 88. The holding circuit to the solenoid 96 will be broken and the controller 9| will be opened, thereby stopping the spindle drive motor I5 and the cam shaft drive motor 46. Since both motors are stopped instantly, the tools driven by the cam shaft 36 will not be damaged byvengagement with a nonrotating work piece.

'I'he overload control 91 is placed in series with the spindle drivemotor l so that if the motor I5 should become overloaded the overload control 91 will open and thereby stop the spindle drive motor l5 and the cam shaft drive motor 46. This overload control is thus a safety measure for the spindle drive motor l5 and insures stopping of the cam shaft drive motor 46 whenever the spindle motor I'5 is halted.

A thermal controlhaving blades 98 and 99 is placed in series with the cam shaft drive motor 46 so that if the motor 46 should overheat the circuit to the motor will be opened and thereby stop the same. A manual start button |00 provides means for initially starting operation of the screw machine.

Whilethe apparatus disclosed and described herein is a preferred form of the invention, yet it is to be understood that mechanical modifications can be made without departing from the spirit of the invention, and that all such modications as fall within the scope of the appended claims are intended to be included herein.

Having thus fully described our invention what we claim as new and desire to secure by Letters Patent is:

1. A screw machine comprising a base member having a bottom wall, a spindle supported by said base member, a variable speed drive unit and an electric motor for the same supported by said base member and disposed adjacent said bottom wall, an output shaft extending from said variable speed drive unit, support members extending upwardly from said bottom wall, selfaligning bearings carried by said support members, a drive shaft disposed Within said selfaligning bearings and coupled to said output shaft in alignment therewith, pulley means carried by said drive shaft, belt means extending from said pulley means to said spindle for driving the same, an idler pulley in engagement with said belt means, and switch means adapted to be actuated by said idler pulley if said belt means should leave said idler pulley for stopping operation of the screw machine.

2. In a screw machine, a base member having a bottom wall, a spindle supported 4by said base member, a cam shaft supported adjacent said spindle, a variable speed drive unit and an electric motor for the same supported by said base member, means drivingly connecting said variable speed drive unit to said cam shaft, a second variable speed drive unit and electric motor for the same supported by said base member adjacent said bottom wall, 'support members extending upwardly from said bottom wall, selfaligning bearing members carried by said support member, a drive shaft disposed within said self-aligning bearings and connected to said second variable speed drive unit, pulley means carried by said drive shaft, belt means extending between said pulley means and said spindle to drive the same, an idler pulley engaging said belt means, and switch means adapted to be actuated by said idler pulley if said belt means should leave said idler pulley to stop said motor for said variable speed drive unit for said cam shaft,

WILLIAM E. JOYCE WILLIAM H. HIMES. DELBERT I. WILSON. 

